1964f-85

I have a mild 68 Toro 455 in my 64. Comp Cam, adjustable rockers on stock C heads, edelbrock dual plan, summit HEI and W-30 exhaust manifolds.

Currently I am running a Demon Vacuum secondary 750. With this carb I have had eratic vacuum readings, rough idle, it kocks so much that I have almost no vacuum advance, light somke at idle, but it drives great.

I am concerned that there is something wrong with the carb and that the motor is running dangerously lean.

I installed a Q-Jet that I had lying around and the engine ran "lazy" but the idle was smooth, no smoke and I could put a good 1/4 turn of timimg into it before it started to knock.

I am thinking about rebuilding the Q-jet again, but this time I want to go to summit and get the correct jets, needles, carriers etc to tune this for a BB Olds.

My question is, has anyone jetted a Q-jet for a 455, if so what jets etc did you use? HAs anyone encountered a similar situation. My instinct is to just rejet it to the factory 4-speed specs.

Thanks for the help!

dc2x4drvr

There's a LOT of OLDS guys running Q-Jets on their cars...
There are better places to buy Q-jet parts, check here
www.gesslerheadporting.com/ and here www.carburetion.com/quadrajet.asp
Post details on your cam/etc. for input on carb jetting.

442scotty

You also might want to consider having you HEI recurved to the cars specs...I purchased a DUI distributor recurved to my specs and it made a huge difference..

And to get the fuel mixture right its a good idea to use an air fuel ratio guage to set up the carb..if you dont mind cutting a hole in your front pipes for sensor bungs...

I have an edelbrock carb and it was real easy to set up using the AF guage..

1964f-85

Sound advise, I just pulled my cruddy old q-jet out of storage. The 1st one I rebuilt was a 1977 model, this one has no part number, just the number 77 stamped in it.
Is is a BOP straight input carb and all of the metering rod part numbers match up with thos of a 68-69 olds big block, so I think i am going to rebuild this one instead.
One odd thing, it has a small piec of sheet metal tack welded from the factory to the underside of the right upper secondary butterfly, I have never seen that before.

dc2x4drvr

Can you post a pic of the '77' carb, the later units were 800cfm, and depending on the year are good performance carbs.

1964f-85

The carb is in pieces, soaking in my parts cleaner.
I cannot find any reference as to what a "77" stamp on the main body, throttle plate and top plate of this carb represents.
Is it correct that early carbs used a "dog tag" ID plate rather than a stamped casting number?

I'll post a photo when it comes out of the parts washer, I do know it is an earlier Q-Jet, it has minor differences to my mid 70's q-jet, like it has removable steel well plugs, the newer one dosen't.

dc2x4drvr

The stamped p/n should be on the vertical rib on the throttle body driver side. Starts with either a "70" or "170". very early Q-jets had tags, the steel well plugs may have been installed on a previous rebuild.